System for removing and refitting rigid covers on bulk-carrying railway wagons

ABSTRACT

A system for removing and refitting rigid covers on rail wagons including a rubber tyred gantry crane with a laterally moving trolley from which a spreader for attaching to a cover is attached via skewed cables to reduce sway and rotation. The spreader engages the covers via electromagnets and moves the covers to hinge on a side lip of the wagon for loading. The cover is replaced by the reverse procedure. Optionally the electromagnets are used to activate a latching mechanism for securing the covers.

FIELD OF THE INVENTION

The present invention relates to the handling of rail wagon covers, in particular an automated system for uncovering and covering a rail wagon with a rigid cover at a bulk loading facility.

BACKGROUND TO THE INVENTION

Traditionally in Australia coal rail wagons have had open tops when in transit. Consequently a considerable amount of dust is lost from such wagons and deposited along the train lines and adjoining properties. This is clearly undesirable due to the environmental impact of the coal dust. Moves are now afoot to introduce legislation to mandate the use of covers on coal wagons. As well as preventing product loss, covered wagons also prevent product contamination and protect against rain and snow.

A conventional approach to handling wagons covers at bulk loading facilities is to remove the cover before the loading facility, transport the cover around the facility and refit the cover once the wagon has been loaded. This requires a large area for temporary storage of covers and a convenient pathway around the loading facility.

Large mobile or fixed gantry cranes are used to remove and refit the cover, which require the wagons to be stationary. This approach is unsuitable for coal loading facilities as they are designed to operate with continuously moving wagons. It is not feasible to repeatedly stop and start a large coal train.

Alternative systems for removing and refitting wagon covers suitable for use with continuously moving wagons are disclosed in US patent publication U.S. Pat. No. 7,878,124 B2 and US patent application publication US 2016/0046304 A1. In these systems wagon covers are attached by hinges to a wagon and removed and replaced with either a system of helical tracks engaging the covers or an elaborate gantry system. Such systems require a considerable area before and after the loading facility which may not be available, and also require complicated hinging and latching arrangements to be fitted to each wagon and cover with their inherent cost and maintenance issues.

The object of this invention is to provide a system for removing and replacing rigid covers on rail wagons requiring minimal infrastructure and wagon componentry to alleviate the above problems, or at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION

In a first aspect the invention provides system for removing and refitting rigid covers on rail wagons, comprising a gantry crane with a laterally moving trolley and a suspended spreader with means for engaging a rigid cover.

Preferably the spreader is suspended from the trolley by skewed cables and electromagnets attached to the spreader engage magnetically susceptible pads attached to the cover. The spreader may include side skirts for engaging the rigid cover.

In preference the gantry crane further comprises rubber drive wheels, may run on rails, or may be fixed in position and comprise a longitudinally moving bridge.

In preference the electromagnets actuate a locking mechanism to secure the covers to the wagons, and preferably the locking mechanism comprises a locking bar movable under a lip of the side of the wagon.

Preferably the locking mechanism further comprises first and second opposed cranks, and wherein vertical displacement of the magnetically susceptible pads results in a vertical movement of the locking bar, and wherein rotational movement of the magnetically susceptible pads results in a horizontal movement of the locking bar.

Preferably rotational movement of the magnetically susceptible pads is effected by energizing the electromagnet and vertical movement of the magnetically susceptible pads is effected by the weight of the spreader.

Preferably the wagon cover is formed of resilient material to accommodate vertical and rotational movement of the magnetically susceptible pads, and the electromagnets and the magnetically susceptible pads are disposed at a non-zero angle to each other. The side edge of the electromagnets is preferably aligned with the centre of the magnetically susceptible pads.

It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

FIG. 1 shows a system for removing and refitting rigid covers on rail wagons according to the present invention.

FIG. 2 shows a rigid cover for a rail wagon.

FIG. 3 shows a gantry crane with a spreader for attaching to rigid rail wagon covers.

FIGS. 4A to 4G show the sequence of removing a rigid cover from a rail

FIGS. 5A to 5G show the sequence of de-activating a latch mechanism for securing a rigid cover to a rail wagon.

DRAWING COMPONENTS

The drawings include the following integers:

-   10 system for removing and refitting covers -   20 rail wagon -   22 lip of side wall -   40 rigid wagon cover planar top -   42 planar top -   44 side skirts -   48 steel pads -   60 gantry crane -   61 bridge -   62 legs -   63 rubber tyred wheels -   65 drive/control cabinet -   70 trolley -   72 (skewed) suspension ropes -   80 spreader -   81 planar body -   82 side skirts -   84 electromagnets -   100 locking mechanism -   110 wagon side -   112 wagon side lip -   120 wagon cover -   122 steel pad -   124 tie bar -   130 electromagnet -   140,142 links -   150,155 cranks -   160 locking bar

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of the invention refers to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

The present invention provides a system for removing and refitting rigid covers on rail wagons gantry cranes to minimise infrastructure, and simple rigid covers for the wagons that don't require any elaborate hinging means. Preferably rubber tyred mobile gantries are used, however, rail mounted or fixed gantries are also anticipated by the invention. The gantry crane can match the speed of a moving wagon and deploy a spreader via skewed suspension ropes to engage the covers with the aid of electromagnets. The covers are lifted up, moved laterally and lowered again to hinge on the side of the wagons which are then loaded. Once loaded the reverse procedure replaces the covers. As part of the system a latch mechanism is provided for securing covers to wagons.

As the system for refitting covers is essentially the same as the system for removing covers, but operating in reverse, only the system for removing covers will be shown in the figures and discussed in detail. The system for refitting covers will be discussed in brief focussing on any differences to the system for removing covers.

The system for removing wagon covers is shown as 10 in FIG. 1 and comprises a rail wagon 20 with rigid cover 40, and mobile gantry crane 60 with suspended spreader 80 for engaging the rigid cover.

The rigid cover 40 as seen in FIG. 2 comprises a gel-coated fibreglass sheet on a stout frame of extruded aluminium angle around the edge with tee section ribs. The cover includes a planar top 42 and side skirts 44 for engaging the sides of the wagon. Steel pads 48 are located on top of the cover for engagement with electromagnets to move the cover. A cover typically weighs some 200 to 300 kg which is sufficient for the cover to rely on gravity alone to stay engaged with a wagon. The side skirts ensure that there is no lateral movement of the cover.

The gantry crane 60 is shown in FIG. 3 with suspended spreader 80 for engaging the wagon covers 40. The gantry crane comprises a bridge 61 and four legs 62, each including an electric motor (not shown) for driving wheels 63 with rubber tyres. Trolley 70 traverses the bridge powered by electric motors (not shown). Drive/control cabinet 65 houses control equipment and a diesel motor driving an alternator to power the electric motors and control system.

The trolley 70 includes four hoists (not shown) which control suspension ropes 72 from which the spreader 80 is suspended. The suspension ropes are skewed both longitudinally and laterally to minimise swaying of the spreader. The spreader comprises a planar body 81 and side skirts 82 for engaging with the side skirts 44 of a rigid wagon cover 40. The spreader also holds electromagnets 84 for engaging with the steel pads 48 on the wagon cover thus allowing the cover to be controllably raised and lowered.

The process of removing a cover from a wagon will be discussed with the aid of FIGS. 4A to 4G.

The cover removing process is under the control of an automated control system located in the drive/control cabinet 65 which allows the gantry crane 60 to operate autonomously. The process is triggered by the detection of a wagon with the aid of an optical detector looking for the leading edge of a wagon 20. The wagons are fitted with RFID transponders which allow their identities to be read, from which the type of wagon and pertinent characteristics for use by the control system can be determined such as the height and width of the wagon and the position of the steel pads 48 used to engage with the electromagnets 84 of the spreader 80. Once a wagon has been detected and confirmed by the presence of an RF transponder the gantry crane will move from its parked position until it can longitudinally align the electromagnets 84 with the steel pads 84 and match the speed of the wagon with the aid of a speed sensor such as a back scattering Doppler radar. The control system uses the edge detection and measured speed of the wagon together with the known wagon parameters to produce an appropriate acceleration profile for the gantry and controls the gantry drive motors to achieve such.

As the gantry crane 60 matches the speed and position of the wagon 20 longitudinally as discussed above, the trolley 70 will move across the bridge 61 if needed to laterally align the electromagnets 84 with the steel pads 48. After the initial alignment the wagon 20 cover 40, trolley 70 and spreader 80 will be as per FIG. 4A. The electromagnets 84 are energised as the trolley hoists let out the suspension ropes 72 to lower the spreader until it engages with the cover and the electromagnets 84 engage with the steel pads 48 as shown in FIG. 4B. Any small alignment errors between the spreader and the wagon cover are overcome by the attraction of the electromagnets to the steel pads. The suspension ropes 72 will then be retracted to raise the spreader 80 and attached cover 40 until they are clear of the top of the wagon as seen in FIG. 4C. The trolley will then move the spreader and cover laterally and lower them again until a first side skirt of the cover engages the side of the top lip 22 of the wagon sides as shown in FIG. 4D. The suspension ropes will then be let out, allowing the cover and attached spreader to pivot about the top lip of the wagon sides until the second side skirt of the cover comes into contact with the side of the wagon as per FIG. 4E. The electromagnets will then be de-energised to allow the spreader and cover to separate and the suspension ropes retracted to raise the spreader clear from the cover and wagon as shown in FIGS. 4F and 4G. The gantry crane can then be moved back to its parked position ready to deal with another wagon whilst the uncovered wagon proceeds through the loading facility carrying the cover on its side.

Once the wagon has been filled and cleared the loading facility the cover is refitted by a second gantry crane. The cover refitting process is simply the reverse of the cover removing process, following the sequence shown in FIGS. 4G to 4A.

The system has been shown and described using rubber tyred mobile gantry cranes, however other forms of gantry crane may also be used. In a second embodiment of the invention a rail mounted gantry crane is used. In this embodiment tracks for the gantry crane are laid either side of the tracks for the wagon. In a third embodiment of the invention a fixed gantry is used which allows for longitudinal movement of the gantry bridge. In applications where the rail wagons are not required to move continuously a still further embodiment is applicable in which the gantry crane does not move longitudinally, having the wagons shunted into position instead.

In the embodiments of the invention described so far the covers have been retained on the wagons by gravity alone, relying on the significant weight of the cover to resist displacement by wind or the air resistance inherently created by a moving train. In a further embodiment of the invention the cover is augmented by a latching mechanism to secure it to the wagon. The latching mechanism is activated by the already present electromagnets used to lift the covers.

A latching mechanism is shown in conjunction with cutaway views of a side of a wagon and a wagon cover in FIGS. 5A to 5C. The figures show the sequence by which the latch is disengaged; engagement of the latch is achieved by the reverse of the sequence. The figures by necessity show the components' relative sizes, shapes, positions and movements out of proportion in order to convey the underlying mechanism involved.

FIG. 5A shows a latching mechanism 100 securing a wagon cover 120 to a wagon side wall 110. In essence a locking bar 160 sits under a side lip 112 of the side wall and via various linkages holds the cover 120 in place. FIG. 5A only shows a mechanism for one side of a wagon. In practise a mirror image version of the mechanism is used to secure the other side of the wagon. Typically two pairs of mechanisms, one fore and one aft would be used to secure a cover at four points. The mechanism is activated/deactivated by an electromagnet 130 in conjunction with a steel pad 122 embedded into the cover 120. In this figure the electromagnet has just come down into contact with the pad 122 and is not influencing the mechanism. The electromagnet is rigidly held by a spreader (not shown) which is similar to the spreader 80 seen in earlier figures, but arched to accommodate an arched cover. Tie bar 124 joins first and second sides of the wagon cover together and pivotally connects to the fulcrum of opposed cranks 150 and 155. The cranks are in turn pivotally connected to the locking bar 160 and the steel pad 122 via links 140 and 142. As the cranks are opposed to each other a differential movement of the links is required for them to move the locking bar horizontally.

To disengage the locking bar 124 from under the lip 112 both a vertical movement as shown in FIG. 5B and a horizontal movement as shown in FIG. 5C is required. From the position in FIG. 5A the vertical movement is achieved by the electromagnet 130 pushing down on the centre of the steel pad 122 and moving the connected mechanism in a common mode manner. Once in the FIG. 5B position horizontal movement is achieved by actuating the electromagnet 130 which attracts the steel pad 122, pivoting it about its centre point to provide a differential mode movement to the connected mechanism.

In FIG. 5B the electromagnet 130, (attached to the spreader) has been moved downwards from the position shown in FIG. 5A and the steel pad 122 moved down in unison. The steel pad remains at an angle to the bottom face of the electromagnet as it is not energised. As the steel pad is embedded in the wagon cover, the wagon cover will also move down in unison, but will bend slightly as it is restrained by the tie bar 124 sitting atop the wagon side 110. Links 140 and 142 will also move downwards and attempt to act on the short ends of the cranks 150 and 155. However as the cranks are opposed to each other and both connected to the locking bar 160, the cranks which have their fulcrums pivotally connected to the tie bar 124 will not pivot, but instead will move down in unison and bend the tie bar. Finally, the locking bar 160 will move down in unison with the other components and is disengaged vertically from the lip 112 of the wagon side.

In FIG. 5C the electromagnet 130 is energised and attracts the steel pad 122 to its bottom face. The steel pad rotates about the point previously in contact with the pad and consequently provides a differential movement to the links 140 and 142, moving link 140 upwards and link 142 downwards. This differential movement allows the connected cranks 150 and 155 to rotate about their fulcrums connected to the tie bar 124 and impart a horizontal movement to the locking bar 160. The lock bar moves out from underneath the lip 112, freeing the cover 120 to be lifted up and off the wagon as discussed in relation to FIG. 4A to 4G.

To engage the latching mechanism 100 the electromagnet 130 is de-energised. Gravity will then be free to act on the locking bar 160, pulling it downwards, and due to the action of the cranks 150 and 155 move it horizontally until it sits under the wagon lip 112. Subsequent raising of the electromagnet will allow the various components to return to the positions shown in FIG. 5A, engaging the locking bar fully to retain the cover 120 in place.

The sequence of using electromagnets to latch and unlatch the cover is readily integrated into the cover removal and replacement process described in relation to FIGS. 4A to 4G. The electromagnets would not be energised when the spreader is moving down towards the cover as in FIG. 4A, but instead be energised once the spreader has engaged with the cover and the skewed lines allowed to slacken. When replacing the cover the latch is automatically activated when the electromagnetic is de-energised.

The movement of the various components relies on resilience of both the cover 120 and the tie bar 124. The resilient deformations are only of the order of a few millimetres in components that span several metres and can be handled by many different materials. The cover is preferably made from thermo-formed 3 mm polycarbonate corrugated sheets, allowing a cover for a 15 metre wagon to weigh approximately 150 kg and still be suitably rigid to allow for handling and suitably resilient to allow the locking mechanism to function. The tie bar and other components of the linkage mechanism can be made from mild steel.

Further downward vertical motion of the spreader, from the “just touching” condition of FIG. 5A, is not directly controlled, but instead depends on the weight of the spreader and the resilience of the wagon cover. With the cables suspending the spreader now slackened the deformation of the wagon cover must be limited so that the bottom face of the electromagnet sits at an angle to the steel pads to allow for the common mode downward movement of the latching mechanism followed by the differential mode movement when the electromagnet is energised.

In practise a 300 kg spreader sitting on wagon cover as described above will deform the cover such that the steel plates rotate by approximately 1.5%. Starting with a differential slope of roughly 3.5% this will leave a 2% slope. A steel pad of approximately 200 mm will give an airgap of approximately 2 mm and subsequent differential movement of the links of 4 mm. Once amplified by the cranks, which have arm lengths in the ratio of 1:10, the lock bar is displaced 40 mm horizontally when the electromagnet is energised or de-energised.

A system employing four commercially available electromagnets, each rated at 500 kgf will provide sufficient holding force to raise the combined weight of the spreader and cover (approximately 450 kg) and also provide sufficient force to operate over the 2 mm airgap to rotate the steel pad as in the transition from FIG. 5B to FIG. 5C.

The reader will now appreciate the present invention which provides a system for removing and replacing rigid covers on rail wagons requiring minimal infrastructure and wagon componentry. The use of skewed suspension ropes greatly reduces any sway or rotation of the cover as it is moved. Optional latches secure the cover for high wind situations.

Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

In the present specification and claims (if any), the word “comprising” and its derivatives including “comprises” and “comprise” include each of the stated integers but does not exclude the inclusion of one or more further integers. 

1-15. (canceled)
 16. A method for removing a rigid cover from a rail wagon, comprising steps of: detecting a presence of a rail wagon; longitudinally aligning a gantry with the rail wagon by aligning one or more magnets fitted to the gantry with one or more magnetically susceptible pads fitted to a cover for the rail wagon; matching a speed of the gantry to a speed of the rail wagon; laterally aligning the one or more magnets with the one or more magnetically susceptible pads; lowering the one or more magnets to engage the one or more magnetically susceptible pads; raising the one or more magnets, thereby raising the one or more magnetically susceptible pads, and thereby raising the cover; moving the cover laterally; lowering the cover so that a first side skirt of the cover engages with a side of the rail wagon; pivoting the cover about the side of the rail wagon until a second side skirt of the cover comes into contact with the side of the rail wagon; and disengaging the one or more magnets from the one or more magnetically susceptible pads.
 17. The method of claim 16, further comprising the step of: unlatching the cover from the rail wagon before raising the cover.
 18. The method of claim 17, wherein the unlatching is accomplished by: engaging the one or more magnets with the one or more magnetically susceptible pads.
 19. The method of claim 16, further comprising the step of: attaching the one or more magnets to a spreader.
 20. The method of claim 19, further comprising: attaching the spreader to the gantry via skewed cables.
 21. The method of claim 16, wherein the detecting is accomplished by: reading a radio frequency (RF) transponder fitted to the rail wagon.
 22. The method of claim 21, further comprising: determining a position of each of the one or more magnetically susceptible pads on the rail wagon using data from the RF transponder. 